RFR: 8377427: Reduce substring allocations in Color.web(String, double) [v10]

[Andy Goryachev]

On Thu, 19 Feb 2026 19:12:12 GMT, Michael Strauß <mstrauss at openjdk.org> wrote:

>> to ensure the behavior of adjacent values, as it is not covered just by the random numbers (what is the probability of selecting two adjacent random values?)
>
> Hmm... but why? It seems to me that you're suggesting to test some kind of edge case, but I don't understand what the significance of closely adjacent values is in this test. In this test, we parse random number strings with both algorithms, and compare their bitwise equivalence. Since the numbers were random to begin with, a number right next to it is equally random. I don't think this adds any relevant test coverage.

you are bringing a non-trivial algorithm, and I would like it well tested.

in fact, I would suggest adding one more test for binary patterns such as 0x0...01, 0x0...10, ... 0xff..ff, 0xff..fe - walking ones, walking zeros, filling ones/zeros from one end, from the other end, 0xaa/0x55.  this is different from random fuzzing but I feel is necessary simply because the search space is just too great (~2^64)

the test patterns would be procedurally generated, then for each pattern use
long -> Double -> String -> parse -> compare with Double

-------------

PR Review Comment: https://git.openjdk.org/jfx/pull/2069#discussion_r2829748990